It is known to secure on the cooling radiator of a motor vehicle a further heat exchanger which may for example be a condenser of an air conditioning installation, or a low temperature secondary radiator for supplying a radiator for cooling supercharging air for the engine.
The main heat exchanger and the secondary heat exchanger are arranged in generally parallel planes, such that the fresh air which is drawn from outside the cabin of the vehicle can cool both the fluid flowing in the main heat exchanger and that flowing in the serpentine tube of the secondary heat exchanger. The fluid flowing in the main heat exchanger is then the cooling fluid for the engine, while that flowing in the serpentine tube may be a refrigerant fluid where the secondary heat exchanger is a condenser, or alternatively, it may be the same cooling liquid as is flowing in the main heat exchanger in the case where the secondary heat exchanger is used in the cooling of supercharging air as mentioned above.
The secondary heat exchanger commonly has a serpentine tube which comprises parallel tube sections joined in pairs by U-shaped bends or crook portions. The parallel tube sections and the bends may typically be of circular or flattened cross section, being associated with cooling fins. The secondary heat exchanger is usually fastened to the main heat exchanger by means of resilient pegs, of which there may be four for example. These pegs are joined firstly to the bends of the serpentine tube, and secondly to anchor points which are provided on the main heat exchanger, and typically on the water boxes of the latter.
Since these heat exchangers are mass produced and subject to dimensional variations, it often happens that the anchor points of a given main heat exchanger do not exactly coincide with the corresponding elements of the serpentine tube of the secondary heat exchanger which are to be anchored at these anchor points. This gives rise to problems during assembly of the apparatus.